The present application relates to the transference of information across an airgap separating a receiver from a transmitter. It finds particular application in the context of computed tomography (CT) imaging modalities, which may be utilized in medical, security, and/or industrial applications, for example, where data is transferred between a rotating member and a stationary member via a contactless transfer system. However, it may also apply to other applications where data, such as image data and/or control data, for example, is wirelessly transferred between a transmitter and a receiver.
Today, CT imaging modalities (e.g., including single-photon emission computed tomography (SPECT) systems) are useful to provide information, or images, of interior aspects of an object under examination. Generally, the object is exposed to radiation comprising photons (e.g., such as x-rays, gamma rays, etc.), and an image(s) is formed based upon the radiation absorbed and/or attenuated by interior aspects of the object, or rather an amount of photons that is able to pass through the object. Generally, highly dense aspects of the object absorb and/or attenuate more radiation than less dense aspects, and thus an aspect having a higher density, such as a bone or metal, for example, may be apparent when surrounded by less dense aspects, such as muscle or clothing.
CT systems are typically configured to generate volumetric data corresponding to an object under examination. To generate this volumetric data, the CT system is generally configured to rotate a radiation source and detector array about the object under examination (e.g., causing the object to be viewed from a plurality of angles). For example, the radiation source and/or detector array may be mounted to a rotating member (at times referred to as a rotor) configured for rotation relative to a stationary member (at times referred to as a stator) configured to support the rotating member.
Given that the radiation source and detector array are mounted on the rotating member, power and/or control information (e.g., instructing the radiation source and/or other electronic components how to operate) are typically supplied to the rotating member from the stationary member. Moreover, imaging data (e.g., data generated in response to the detection of radiation by the detector array) and/or status information (e.g., regarding a status of the radiation source and/or other components attached to the rotating member) are typically transferred from the rotating member to the stationary member (e.g., for further processing and/or to be displayed to security/medical personnel). It may be appreciated that the volume of data transferred, particularly with respect imaging data, may be quite large. For example, some imaging modalities may require transfer speeds of up to 1.5 or more gigabits per second (e.g., particularly if the rotating member does not comprise a storage medium to temporarily store data until it can be transferred).
Conventionally, slip-ring assemblies have been used to transfer power and/or information (e.g., control information, status information, and/or imaging data) between the stationary member and the rotating member or more generally between a movable member and a stationary member (or between two movable members) through the physical contact of two materials (e.g., via a sliding contact). For example, a slip-ring attached to the stationary member may comprise metal brushes that are configured to physically contact electrically conductive surfaces (e.g., metal brushes) comprised on a slip-ring attached to the movable member, allowing power and/or information to be transferred between the stationary member and the movable member through one or more metal brushes.
While the use of slip-ring assemblies has proven effective for transferring power and/or information between a stationary unit and a movable unit (e.g., such as a rotating member) and/or between two movable members, conventional slip-ring assemblies may generate dust or particles (e.g., as metal brushes wear), may be unreliable (e.g., again as contact surfaces, such as metal brushes, wear), and/or may be noisy (e.g., as surfaces rub against one another), which may cause interference during CT imaging. Other drawbacks of slip-ring assemblies may include cost and complexity of manufacture due to special materials and/or mechanical precision that may be required.
More recently, contactless assemblies have been devised to transfer the data between a rotating member and a stationary member. For example, U.S. Pat. No. 5,577,026 (assigned to Analogic Corporation), incorporated herein by reference, describes an approach for contactless assemblies to transfer data. While such an assembly may overcome many of the aforementioned drawbacks to a slip-ring assembly, the amount of data capable of being transferred via the foregoing contactless assemblies has been limited.
For example, such contactless assemblies implement a relatively straightforward binary signaling technique. That is, data is converted into an analog domain, with respective signals (or samples) corresponding to one of two possible binary values (e.g., a first value corresponding to “0” and a second value corresponding to “1”). Stated differently, the signal that is generated may be one of two possible variations, where a first variation is indicative of a “0” value and a second variation is indicative of a “1” value (e.g., such that respective samples represent a single bit of information). While such a technique may be relatively easy to implement (e.g., resulting in minimal data processing by a transmitter and/or receiver performing the conversation), such assemblies are not easily scalable. That is, to increase data capacity or bandwidth of the contactless assembly, additional hardware must be purchased (e.g., such as a wider bandwidth data-link) and/or by incorporating multiple data-links in parallel, for example. Thus, to increase data capacity, hardware modifications may be required that add costs and/or design constraints to the imaging system.